Density functional study of H2 desorption from monohydride and dihydride Si(100) surfaces

A. Vittadini, A. Selloni

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We present a density functional study of H2 adsorption on and desorption from Si(100)2×1 monohydride and Si(100)1×1 dihydride surfaces, carried out using a slab geometry with large supercells. For the monohydride surface we find that two distinct mechanisms - i.e. the recombination of two H atoms sitting either on the same dimer or on adjacent dimers along a row - yield desorption barriers in agreement with experiment. For the dihydride surface, the preferred pathway involves the desorption of two H atoms belonging to the same SiH2 unit. This is followed by a local structural rearrangement, leading to the formation of a surface dimer, and making the overall reaction slightly exothermic. The corresponding adsorption barrier, ≈ 2 eV, is large with respect to that inferred from desorption experiments.

Original languageEnglish (US)
Pages (from-to)334-340
Number of pages7
JournalChemical Physics Letters
Issue number3-4
StatePublished - Mar 24 1995
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry


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